Rotary lock-stitch sewing machine



'sg t. 25, 1923.

- 1,469,066 F.J.T.BELL.ET AL ROTARY LOCK STITCH SEWING MACHINE Filed Dec. 9, 1921 2 Sheefcs$heet 1 Sepc. 25, 1923. 1,469,066

F.- J. T. BELL ET AL ROTARY LOCK STITCH SEWING MACHINE Filed Dec. 9, 1921' 2 She ets-Sheet 2 jnven/ors v Patented Sept. 25, 1923.

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FREDERICK JOHN rename BELL e naanrcnorn nnm, or nsnron-nnnnn tynnj 1 ENGLAND. r V

ROTARY LOCK-STITCH snwrns macnrivn 1 Application filed December 9,1921. Serial No. 521,139.:

To-aZZ WhOflZ it may concern:

Be it known that-we, FREDERICK JOHN TURNER BEL and HARDY CECIL. BELL, sub. jects .of the King of Great Britain and Tie "land, and residents of Ashton-under-Lyne in the county of Lancaster,- England, have invented certain Improvements in and Relatingto Rotary Lock-St1tch Sewlng Machines, of which the following is a specnica tion. i

This invention relates to rotary lockstitch sewing machines of that typeknownas the two-reel, wherein a bobbin cheese or the like of thread is used as the underthread in the formin which it comes from the manufacturertwithout being rewound on spools. (Theinvention may however also be applied to 21:YI'13ChlIl6' wherein the underthread has been wound on a spool.) In-such machines,

:as is well known, the underthread is led to the sewing point of themachine, and a' rotary hook engages the loop of thread formed by the needle and carries the said loop clear around the casing containing the reel or bobbinlo't underthread, the loop being. then pulled up to form the stitch,

The objector our lIlVeIltloIlls to provide improved mechanism whlch will allow :of

the easypassage of the needle thread loop around the reel orbob'bin casing (hereinafter referred to as' the bobbin casing) without strain on the will from its formation prevent the contamination of the loop thread with lubricating' oil; and which will present other advantages to be hereinafter referred to. In carrying it into effect we provide a rotary-hook adapted to engage the loopxot needle thread and carrying same around the iunderthread bobbin casing, the axis of rotation; of the hook being inclined to the vertical. The plate carrying the bobbin casing is supported by the ring bearing the loop taking hook, and the longitudinal axis of the said bobbin casing is vertical and'so of the bobbin casing easily and without jerk, or strain.

said loop which.

A e pl e is providedto prevent needle thread loop becoming entangled'wlth" the mechanismon the reversal of'thelatter and special means are-also provided for ensuring a free passage ofthe needle thread loop,- after it has passed around the bobbin} easing and is passing the anchoringd-de:

viceused to bin casing. r i l l .In addition to the above, ,the-- invention provldes for improved driving-means forthe lock stitch mechanism. 7

The invention will now be with referenceto the accompanying,drawin s-,wherein:

V *igure 1 is an end elevation of thezmecha nism, looking from the operative end of the sewing machine table; I I

Figure 2 is a plan of same, the machine throat plate beingremoved V a Figures 3', 4 and. 5 are details;

Figure 6 is abo'ttom plan of the machine table, showing drivingand' other :niechan1sm; Referring-tol igures'1 and-2, l is the sew-, ing:machine head, 2 the presser foot, and 3 the'needle shaft with needle-54;. 5 'isfthe throat plate of the machinei fitting on machine table 6 abovethelock stitch -mechanism. ,All or" these parts l'to 6. may be of the usual or any convenientconstruction. To the underside ofthe machinetablefi is se cured abracket 7 for the-purp'oseot supporting the improved lock stitch mechanism, The latter comprises a hook ring 8 cutaway at- 9 (Figure 2) to form a hook toitake'the needle thread.loop.- The ringSis mounted upon a carrier of truncated conical formaprevent the rotation of the bobtion 10,=which may be cut away :a's-shown in casing- 15, are shown in' the details Figures 3v and 4 in rearelevation and plan respectively, and in plan inrFigure ti," the latter from a point of view at the operative endoie "any destined- 17 on the bobbin casingfthei'directionof.

the machine table, as in Figure 2;, and ure 3 .an' d.4 froni'fa, diametrically opposite point. It is entirely supported by thehook ring 8, the, edge of, the .later forming. a. race forth'e s'aid"hook ring, and is preventedj from rotating therewith by the stop 17,

shown in F i ures 1 and2 and mo re clearly in the detail igure 5, engaging a pro ection rotation of the hook ring being counterclockwise &S ,VlW6d* 1n the plan, Figure 2).

A further stop 18 prevents rotationiof-the race platewith its bobbin casing lo should the mechanism be reversed 1 9 is a plate spring "secured atone extremity thereof to the wall of'the bobbin'easing l5,"by a screw l9 flas shown. The underthread, in passing from the bobbin contained inthe bobbin casing 15, to the sewing point ofthe' machine',""'passes' between the casing and the spring, the latter thus forming 'sim i tensioning device which may be' adjusted and regulated by the tightening or slackening of thescrew 19 Shallow ribs QOk'ee'p' the needle thread loop from becoming entangled in the tensioningspring 19 in its passage around the bobbin'casing'i The rotation of the hookring 8-with hook 9 being counter clockwise. as", viewed in Figure 2, and the hoolcring 8 supporting within itself 5 the' race plate 14: and the bobbin casing i5 born e by the latter. the continuedrotation of hookrin'g 8 will-tend to keep the projection 17 on the bobbincasing continuously against the'stop,17 Means are there'fore provided to ensure that when the needle thread loopis to be drawn up to form the stitch. there shall be a gap silt ficient forthe purpose between the parts 17 and .17

jection 21, Figures 1, 2, 3 and 4:,this projection being adapted at pre-determined times to be touched. on one side by a toucher leveri22,.attachedto a rocking shaft 23 which is actuated in any convenient manner from the needlearmrmechanisin of the sew-.

ing machine.

The rotation of .the' needle thread loop taking hook on,the hook: ring 8 is effected by spiral gear wheel24,.on the spindle ll, meshing witha toothed pinion 25 fitted upon the end of and C'O aXia-l'with'the driv ing shaft 26,. showninFigure16. 1 This gear- .ing may ,be enclosed inia casinglllfi-the.

' shaft, .26 passing, therein through a a sleeve brackets. 28%? and. driving 7 To this end we fix on the race plate 14 .the hemispherical or bulbous pro-' imFigure 6. The shaft 2 6:may be made adjustable in adi'rection transversely-Jot its length by any convenient means. For instance, the heads .of the. screwsfifii ,mayi fit within 'recesses forined in the bracket '27, in v the screw stem in eachcase passing through a slot; formed atthe bottom of the recess. The screws being slackened, transverse adjustment oftheishaft 26 may be made within the limits of the length of theslots.

This shaft 26 maybe driven fromthe sew ing machine arm mechanism in anymanner, known, in the art. Suchdrivingmeans-are-g' well known and need notbe-described here.

The operation of the machine is as follows The underthread is led trom-the bobbin in thebobbin casing 15th-roughtensiondevic'e 19 to the sewing pointas is"u'su'a' l.f; The needle, descending, forms the needle} thread loop in the gap 1 Figures 2 andffi; '85 andthe hook .9 in. its rotation'engages there-- with and carries it around the-ioutside of---' the hookring-8. As the hoolo9 begins-its ascent towards its highest-point oi itsplanes} oi. rotation, one sideof -the-needle threadtgeo loop slips back from the gap y behind the bobbin casingand is spread therearound, the other side being spread around the hook ring 8 by the continued rascension iot the hook 9 until, when the latteris at about the-e6 position inwhic'h-itis shown ingFigures 1 and2, the take up of the sewing ma chine -comes into :action, draw-ingthe loop smoothly over-the top of the.bobbin. .-cas-c... ing. The loopis shown inFigur-esl and 2AM at the point where the hook9 has=deliveredg one side' th'ereof (under the pullfof the'take up motion) to enable it to continue its rota-1..

7 tion, the other side of the loop having passed. 7 around, the bobbin casing. 15. The relative J05 positions of the hook 9 .and";the...bobbine cas ng 15 at this casting -off? point. entirelydoes awaywithany strainupon the,

needle thread loop, and no ribsor spreaders;

of any kind are.necessarysas has hithertosll-o been the case inlrotary, lock stitchgsewingi machine mechanism-to ensure a smoothIT passage of the loop .aroundi-thei bobbins casing.

Just before the, loop is pulled up'iby the..;11=5\ take up motion the toucher? lever 222130111681 into action, and, descending upon onetsidev of the projection 21; causes.the,raceplate,.;. with the bobbin casingborne-.itheneby to gap between the 7 projection 17 011;. the; bobbin casing and the stop .17' .for the "pass; sageof the loop when beingpullediup.

The, ratio of a complete .needle;;recipr.o-,-

cation to the rotation oft-the hook. 9 -i prefe the needle is on its upward stroke. h'ilst-ww the needle travels upwards to the highest point of its stroke and has partly descended, the hook 9 makes an idle revolution, and by the time it has in its next revolution reached the loop taking position y (Figure 2) the needle has descended and formed the loop for engagement by the hook.

Should the machine be stopped and reversed for any cause just after the needle threadloop has been engaged by the hook 9, there is a danger of the loop slipping ofl? the latter owing to such reversal withdrawing the hook from the loop. To prevent this we provide on the exterior of the bob bin casing and radially thereto at the point shown in Figure 2 and in the detail Figures 3, 4 and 5, a plate 29, over which the needle thread loop passes, to keep it taut upon the hook 9. Reversal of direction of the hook will not with this arrangement draw the hook, out of the needle thread loop. After the hook 9 with its engaged needle thread loop has reached a point about 90 degrees from its loop engaging point there is no possibility of the said loop becoming slack on reversal of the machine, as it is then being spread around the outside of the hook ring 8.

We do not confine ourselves to the exact having a slight axial motion and supported within the rotatable hook ring for which the race plate periphery forms a bearing, a needle gap in said race plate, means for limiting the axial motion of said race plate, and an underthread bobbin casing support ed by the race plate, the longitudinal axis of said bobbin casing being vertical and the highest point in the path of rotation f of the inclined hook ring being approximately level with the upper edge of the 7 a sewing machine, a rotatable hook ring a cut away at one pointtoform a loop taking hook, the axis of rotation of the-said ring p being inclined to the vertical, a race plate having a slight axial motion and supported within the rotatable hook ring for which the race plate periphery forms a bearing,

a needle gap in said race plate, means for limiting the axial motion of said race plate, and an underthread bobbin casing supported by the race plate, the longitudinal axis of said bobbin casing being vertical and the highest point in the path'of rotation of the inclined hook ring being approximately level with the upper edge of the vertical bobbin casing, means for rotating the hook ring, and a plate fitted exteriorly to the bobbin casing near the needle gap therein and below the hook ring to keep the needle thread taut for a space after the hook engages therewith;

3. In combination with the rotary lockstitch mechanism for a sewing machine as claimed in claim 1, a coned member bearing the rotatable hook ring, a spindle formed centrally of said cone, and a driving rod for rotating the said spindle and cone with the hook ring, the longitudinal axis of the driving rod and spindle forming aright angle, and spiral gearing onthe driving rod meshing with spiral gearing on .the spindle.

In testimony whereof we have hereunto set our hands.

HARDY CECIL BELL. 

